β-chlorovinylaldehydes as intermediates in the synthesis of new substituted β–fluoroalkoxyvinyl aldehydes and corresponding alcohols

Abstract

A convenient synthesis of a series of new β-fluoroalkoxyvinyl aldehydes and their corresponding alcohols from β-chloro-α,β-unsaturated aldehydes was developed. The etherification reaction and the carbonyl reduction were successfully achieved, affording the desired products in good yields. The mechanism of the nucleophilic vinylic substitution reaction of the 3-chloro-3-phenylacrylaldehyde has been studied using DFT methods. IRC analysis shows the presence of a hidden intermediate, in agreement with a one kinetic step two-stage process. The isomerization of hidden intermediate Z-3-chloro-3-phenylacrylaldehyde (IntZ) into hidden intermediate E-3-chloro-3-phenylacrylaldehyde (IntE) was explained in terms of the small energy gap difference between the two intermediates IntZ and IntE and the thermodynamic stability of stereoisomer E compared to Z.